<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="vue.js"></script>
</head>
<body>
    <main id="app">
        <h1>{{ des | lowercase}}</h1>
        <h1>{{des |uppercase}}</h1>
    </main>
    <script>
    Vue.filter('lowercase',function(value){
        return value.toLowerCase()
    })
    Vue.filter('uppercase',function(value){
        return value.toUpperCase()
    })
    var vue =new Vue({
        el:"#app",
        data:{
            des:"You ArE beauTiFul"
        },
        filter:{

        }
    })
    
    </script>
</body>
</html>